Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02869379 2014-10-31
01%4801'114
LIQUID FILLER USING SINGLE MOTIVE FORCE
TECHNICAL FIELD
The present invention relates generally to liquid dosing of containers and
more
particularly, a dosing apparatus for producing highly accurate and repeatable
dose
amounts for precisely filling containers using only a single motive force to
produce the
doses such that with each dosing apparatus cycle all containers are
substantially
simultaneously and equally filled.
BACKGROUND OF THE INVENTION
Liquid filling machines of many types and categories are well known in the
patent arts and in commercial practice, One broad category of automatic liquid
fillers is
termed the in-line or linear liquid filler,
In terms of container motion through the machine, in-line filler types may be
of
intermittent container motion or continuous container motion, although the
former
greatly dominate in usage. With continuous motion types, containers are filled
in
groups, corresponding to the number of filling positions, as containers move
continuously from the infeed of the machine to the outfeed. With in-line
intermittent
motion machines, containers are conveyed into the filling machine as a group.
The
container group is positioned and held stationary while each container within
the group
is completely filled with the requisite total till or dose of liquid. After
filling, the
container group is conveyed to the discharge of the machine, a next group of
containers
are conveyed into the machine, and the sequence repeats.
Within the in-line filler category, automatic filling machines are further
categorized and analyzed by type or methodology of induced liquid flow, termed
motive
force. The motive force to cause liquid flow in an automatic liquid filling
machine can
include gravimetric flow, pressurized vessel induced flow, and positive
displacement
pump induced flow.
Gravimetric flow rate can be controlled by the degree of elevation of the
liquid
above the point of dispense or by flow orifice size of the dosing mechanism,
Gravimetric flow as a motive force for filling is tightly constrained to use
only with free
CA 02869379 2014-10-31
OMSOIUSp
2
flowing, low viscosity, homogeneous liquids. Controlled pressure vessel
induced flow
as a motive force is mediated by the gas pressure applied to the liquid and is
generally
constrained to low to medium viscosity homogeneous liquids, and to applied
pressures of
only a few Bars.
Motive force to induce liquid flow in an in-line filler is dominated in
practice and
usage by positive displacement pumps. By general definition, a positive
displacement
pump generates a defined liquid flow per increment of motion under a given set
of flow
conditions, with a given liquid. Many types of positive displacement pumps are
known
and utilized for liquid motive force in liquid filling machines. These include
piston or
linear displacement pumps, where flow rate is determined by speed of linear
motion; and
rotary motion positive displacement pumps, such as gear pumps, lobe pumps,
circumferential piston pumps, progressing cavity pumps, sine rotor pumps,
peristaltic
pumps, where flow rate is defined by rotation rate; and diaphragm pumps where
flow
rate is defined by rate of diaphragm motion. In general usage, piston pumps
and rotary
displacement pumps dominate. Within the rotary pump subcategory, gear pumps
and
lobe type pumps (including circumferential piston) are almost completely
dominant in
application. This is because the range of usage and utility, termed machine
versatility
and flexibility, cannot be rivaled in performance by the other known and
described
container filling methods.
In-line fillers can be further categorized by means and method of defining a
dose,
the quantity of a given liquid to be filled into a given container.
Gravimetric flow, with
the source liquid level controlled allows volumetric dose definition by timed
flow or by
use of volumetric flow meter types. Use of a Coriolis mass flow meter allows
the liquid
dose to be defined on a mass or liet weight basis, Controlled pressure vessel
induced
flow allows volumetric dose definition by timed flow or by use of volumetric
flow
meters. Use of a Coriolis mass flow meter can provide a mass defined dose.
In the predominant oases of use of positive displacement pumps, volumetric
dose
is defined for piston or linear displacement types by control of stroke or
increment of
linear motion. Displacing the piston pumped liquid through a Coriolis mass
flow meter
allows the liquid dose to be defined on a mass or net weight basis. In the
case of rotary
motion positive displacement pumps, volumetric dose is determined by increment
of
pump rotation and displacement of the rotary pumped liquid through a Coriolis
mass
CA 02869379 2014-10-31
OMSOlUSp
3
flow meter can provide a mass or weight defined dose,
Typically, in prior art designs, each dosing pump is controlled and operated
by a
separate servo mode motor drive, typically an electric servo motor and
associated electronic
controls. Taken together, this assembly may be termed a servo-pump. By
example, a filler of
known type with ten filling positions uses ten servo-pumps in its
implementation.
The ability to use a single motive force in a filling apparatus, rather than a
separate
motive force for each filling position may reduce costs. Means of devising a
single motive force
(SMF) filler exist and include a gas head flow compensation methodology where
changesin
flow rates in asynchronously operated flow branches are attenuated using a
passive or active gas
dome. This method exhibits multiple positive displacement (PD) pump
complexities and
degraded performance capabilities, and requires a dose defining flow meter in
each flow branch,
negating much of the substantial cost reduction over the known and accepted
multi-pump
method.
In another SMF method, flow in each flow branch is diverted upon asynchronous
completion of a fill dose in that branch. The method also requires a flow
meter in each flow
branch and suffers from the same list of shortcomings as in the gas head flow
compensation
method.
In most cases where in-line fillers are utilized with positive displacement
dosing
pumps, the configuration constituting the single largest commercial filling
machine
grouping, a discrete positive displacement pump is utilized as the dosing
mechanism at
each and every dosing position, requiring a complete duplication of all dosing
hardware
and controls at each position. So, for example, a six dosing position or six
"filling head"
machine would have six complete and separate dosing pumps, one for each
filling
location, while a ten-head machine would have ten dosing pumps. Each pump
would be
essentially identical with every other in the machine, and each pump would be
associated
with a separate drive mechanism, a separate reservoir or supply feed and
connections, a
separate dose defining mechanism (mechanical and/or electronic) and generally
discrete
controls for flow rate, dose, and for filling head or dosing valve control
tied to that
particular dosing head. A well-known example of a filler as described is the
SERVO/PILL manufactured by Oden Machinery Inc. of Tonawanda NY,
Further, if the filling machine were intended for net weight filling, it would
conventionally have a Coriolis liquid mass flow meter located in the flow
discharge pathway of
CA 02869379 2014-10-31
0114801USp
4
each and every pump. A well-known example of a filler as described is the
NET/MASS
manufactured by Oden Machinery Inc. of Tonawanda NY (US Patent No. 5,996,650).
The result of the described conventional and known in-line filler machine
architecture
or layout is a machine with a high degree of complexity which is directly
proportional to the
number of filling positions, and a cost which is related to the number of
filling positions.
SUMMARY OF THE INVENTION
The subject matter of the present disclosure includes a filling machine for
dosing and
containers that eliminates the requirement for an expensive duplicate dosing
pump and
associated apparatus for each filling head of the machine. A single master
dose pump is
supplied with the liquid to be filled by a single outlet reservoir or by a
single flow source
liquid supply. A single master dose pump may operate as the single motive
force to
provide a master dose which is hydraulically subdivided into a plurality of
equal
subdoses. The single master dose pump may be a positive displacement pump that
is
adjustable in liquid flow rate in order to establish the desired rate of
liquid flow through
the entire liquid flow pathway of the apparatus and into the plurality of
containers to be
filled. In the liquid filling method and apparatus, the entire liquid flow
pathway, from the
master dose pump liquid supply to the plurality of liquid filling heads, when
in operable
condition, may be entirely hydraulic or liquid filled. The master dose
provided by the
master dose pump may be displaced into a liquid product dose distributor. The
dose
distributor hydraulically subdivides the master dose into a plurality of
approximately
equal subdoses, each of which is delivered into one of a plurality of subdose
flow
branches.
The construction of the entire liquid flow pathway of the liquid dosing method
and apparatus is of sufficient dimensional precision that, with each subdose
branch
configured identically, the measured subdose at each dosing position may be
within 3
percent or better of the mean of all subdoses as established by summing the
synchronous
subdoses measured at all operating dosing positions and dividing by the total
number of
operating dosing positions. Each separate subdose branch created by the liquid
product
dose distributor may have an adjustable liquid dose control in its liquid flow
pathway.
The liquid dose control in each subdose branch may be adjustable in
conjunction with
CA 02869379 2014-10-31
0MsOlUSp
the liquid dose controls in all other operating liquid subdose controls in all
other
operating liquid subdose branches for the purpose of establishing each subdose
to be
equal in volume or weight to all other subdoses. The adjustment of each liquid
dose
control in each liquid dose branch may be done manually or automatically,
5 Each subdose branch in the plurality of subdose branches of the
liquid dosing
method and apparatus may be terminated with a precision fast acting dosing
valve or
filling valve or filling head; each filling head constituting one filling
position or dosing
position.
The calibrated master dose pump and the plurality of filling heads in the
liquid
filling method and apparatus may operate synchronously to produce a master
dose
subdivided to a plurality of equal subdoses, each equal subdose simultaneously
delivered
through its respective filling head. The master dose may be directly produced
and
defined by the single master dose pump and directly delivered to the liquid
product dose
distributor. The master dose may be defined and measured by mass or weight.
The
master dose may be produced by placement of a single Coriolis liquid mass flow
meter,
disposed between the outfeed of the single master dose pump and the infeed to
the liquid
dose distributor. The master dose defined and measured by volume may be
produced by
placement of a single volumetric liquid flow meter, between the outfeed of the
single
positive displacement master dose pump and the infeed to the liquid dose
distributor,
The master dose produced by the master dose positive displacement pump may be
established in volume to be equal to tbe desired volumetric sum of all
subdoses in the
plurality of subdoses. The master dose produced by the master dose mass meter
may be
established in mass or weight to be equal to the desired mass or weight sum of
all
subdoses in the plurality of subdoses.
The master dose expressed in volume or weight, may be defined and established
by the formula:
MD = SD, + S2 + + Sõ (1)
where MD is the weight or volume of the master dose, and SD, through Sõ are
the weights
or volumes of the individual subdoses and X is the number of subdoses.
Thus, the master dose, expressed in volume or weight, can be defined and
established by the formula:
MD = SD, x X (2)
where SD, is the desired subdose target set point expressed in volume or
weight.
The calibrated subdose, expressed in volume or weight, can be defined and
established by the formula:
Mix + X (3)
CA 02869379 2014-10-31
014501 LiSp
6
where St), is the calibrated subdose, Moeis the calibrated master dose.
The sequence of calibration leading to subdoses that are equal to one another
and
to the desired or target volume or weight may begin with adjusting the master
dose to be
equal to the target subdose weight or volume multiplied by the number of
dosing
positions, as given by formula (2).
The volumetric displacement dose produced by the master dose positive
displacement pump may be conventionally measured and established by a preset
pulse
count, pulses being generated by a linear or rotary encoder. Alternatively,
the volumetric
dose produced by displacement flow of the master dose pump through the single
volumetric liquid mass flow meter may be conventionally measured and
established by a
preset pulse count, pulses being generated by the volumetric flow meter, In
another
alternative embodiment, the mass or weight dose produced by displacement flow
of the
master dose pump through the single Coriolis mass flow meter is conventionally
measured and established by a preset pulse count, pulses being generated by
the mass
flow meter.
The master dose calibration may begin by measuring the total or summed weight
or volume of all synchronously filled subdoses, together constituting a trial
master dose,
and by counting the total trial dose pulses generated by the master dose pump
encoder or
the master dose volumetric or mass flow meter. The volumetric or mass dose of
the
master dose pump or master dose flow meter may be adjusted to calibrate or
establish the
target master dose by use of the following formula
TARMD X TRIMDPC = TARMDPC (4)
TR1MD
where TARMD is the target master dose, TRIMD is the trial master dose, TRIMDPC
is
the trial master dose pulse count, and TARMDPC is the target master dose pulse
count.
The calibration of each dose branch in the plurality of dose branches to
equalize
each subdose to all other subdoses in the plurality may occur after the master
volumetric
or weight dose set point has been established and may be accomplished by
subdividing
the calibrated master dose into equal parts, each an equal fraction of the
whole, using the
adjustable dose control located in each dose branch. When the subdose is
reduced by
adjustment of the dose control in a given flow branch to correct for a subdose
which is
too large, the subdose will increase at all other operating flow branch
subdose positions,
Conversely, when the subdose is increased by adjustment of the dose control
for a given
CA 02869379 2014-10-31
OMSOlUSp
7
flow branch dosing position to correct for a subdose which is too small, the
subdose will
decrease at all other operating flow branch dose positions. In either case,
the change in
subdose in any one of the unadjusted dose positions will be ratiometric and
proportional
to the summed subdoses of all of the unadjusted dose branches.
Each subdose may be equalized to achieve a target subdose by manipulation of
each dose control in conjunction with all other operating dose controls.
Each dose control may be identical to all others in the operating apparatus
and
each dose control may be adjustable manually or automatically to effect an
increase or
decrease in subdose delivered through its dose branch. Each dose control may
be
adjustable manually with use of an increment of movement register or scale
associated
with each dose control adjustment mechanism, and where each dose control may
be
adjustable automatically by use of a pulse count from an adjustment actuator
associated
with each dose control,
Each dose control may initially be in a neutral dose adjustment position prior
to
subdose adjustment and calibration, allowing the dose branch subdose to be
increased or
decreased by a similar range or increment as necessary. The adjustment of the
dose
control may be incremented in weight or volume calibrated scale divisions
denoting the
amount of subdose adjustment, or in weight or volume calibrated pulses per
increment of
subdose adjustment, the divisions or pulses incrementing up and down from a
zero or
neutral position and defining positive adjustment (larger subdose) and
negative
adjustment (smaller subdose).
All operating dose controls in a plurality of dose controls may be initially
calibrated by first cycling the master dose pump to produce a first sample
subdose at
each dosing position; and then measuring the sample subdose at one dosing
position; and
then adjusting the dose control at that dosing position up or down by an
arbitrary number
of increments or pulses; and then cycling the master dose pump to produce a
second
sample subdose at each dosing position; and then measuring the second sample
subdose
at the same dosing position; and than applying the two subdose measurements to
the
following dose control calibration formula:
FLITILD CUPI (5)
SI
where FTD is the first trial dose in weight or volume, STD is the second trial
dose
in weight or volume, SI is the number of adjusted dose control scale
increments, and
CUPI is the resulting dose control calibrated units per increment value
expressed in
weight or volume per scale increment,
CA 02869379 2014-10-31
OISAS011iSp
8
All operating dose controls in a plurality of dose controls can be
successively and
repeatedly adjusted for improved calibration accuracy by first measuring the
average
quantity of dose change for all subdoses resulting from a previous adjustment
and
calibration; and then correspondingly averaging the scale increments or
divisions or
pulses for all operating dose controls adjusted in the same previous
adjustment and
calibration; and then applying these data to the following dose control
calibration
formula:
ADC = RCUPI (6)
ASI
where ADC is the average dose change across all of the operating dosing
positions,
ASI is the average scale increments of dose control adjustment across all of
the
operating dosing positions, and RCUPI is the resultant recalibrated units per
increment
of dose control adjustment.
Each .subdose adjustment and calibration begins with the collection and
measurement of a trial subdose for each operating filling head. Each trial
dose is utilized
in the dose control adjustment procedure using the formula:
TARSD ¨ TRISD = SDE (7)
where TARSD is the target subdose in units of weight or volume, TRISD is the
trial
subdose in units of weight or volume, and SDE is the subdose error in units of
weight or
volume, and where a positive (+) subdose error signifies a required upward
adjustment of
the dose control to increase the subdose, and a minus (-) subdose error
signifies a
required downward adjustment of the dose control to decrease the subdose.
Each trial subdose error derived from the equation given in equation (7) is
used
to adjust each corresponding dose control using the formula;
SDE = SIC (8)
CUM
where SDE is the positive or negative subdose error, CUPI is the calibrated
units per
increment of adjustment of the dose control, and SIC is the number of dose
control
adjustment scale increments to correct the trial subdose, where a positive (+)
result
requires an upward adjustment of the dose control to increase the subdose, and
where a
negative (-) result requires a downward adjustment of the dose control to
decrease the
subdose.
The adjustable dose control for each subdose filling head or filling position
may
be adjusted as set forth in previously prior to collection and measurement of
a second
CA 02869379 2014-10-31
ONIsOlUSp
9
trial dose from each filling position.
The complete subdose calibration sequence described in equations (7) and (8)
may be repeated on all subdose filling positions until all subdoses are within
an
acceptable percent or measured increment of the common target subdose set
point,
The effect of dose adjustment of the adjustable dose control for one filling
head
upon the dose setpoints of the remaining filling head positions decreases
ratiometically
as the number of operating filling heads increases, such that the dose change
is
proportional on all unadjusted heads but the magnitude of the change on each
filling
head is reduced.
10. One to three repetitions of the calibration sequence described in
equations (7) and
(8) are generally sufficient to achieve a subdose set point accuracy of plus
or minus one
percent of the target subdose common to all filling positions. After the
desired master
close has been established, an alternative method of subdose adjustment and
calibration
may begin with dose cycling the apparatus to produce a synchronous subdose at
each
filling head and then the collection and measurement of one dose head subdose
from a
first filling head, with the dose error of that filling head determined and
adjusted using
the formulas and method given in equations (7) and (8). After adjustment of
the dose
control for the first subdose filling head, the filling apparatus is dose
cycled, producing a
synchronous subdose at each filling head. This described process is then
repeated on a
next filling head, and then the process is repeated sequentially, one filling
head at a time,
until each operating filling head in the plurality of filling heads has been
discretely and
sequentially adjusted. This one head at a time method is continued in sequence
until all
subdoses are measured to be within an acceptable plus Or minus percent or
measured
increment of the common target subdose set point,
One to three repetitions on each filling head of the second calibration method
set
forth in equation (8) are generally sufficient to achieve a subdose set point
accuracy of
plus or minus one percent or better of the target subdose common to all dosing
positions.
In direct comparison with known prior art positive displacement pump liquid
dosing designs, the amount of functionally identical apparatus to implement a
complete
filling position with the present invention is reduced ratiometrically as the
number of
filling positions to be implemented increases. This reduction i$ expressed
quantitatively
as a percentage reduction by the formula:
1 ¨ (1.i- DPx ) x 100 = PR (9)
where DPx is the number of dosing positions, and PR is the percent reduction.
The
comparative ratiometric reduction in apparatus cited in equation (9) allows a
corresponding reduction in overall machine size and footprint. The comparative
,
ratiometric reduction in apparatus cited in equation (9) confers a
corresponding
CA 02869379 2014-10-31
OMSOIUSp
ratiometric reduction in cleaning apparatus, cleaning time, cleaning liquid
volumes
consumed, and effluent volumes generated, when directly compared to known art
liquid
filling machines constructed with equivalent liquid flow pathway components
and
construction. The comparative ratiometric reduction in apparatus cited in
equation (9)
5 conserves a comparable range of use, utility of use and capability and
span of
application,
Expansion of filling heads requires only a change out or alteration of the
dose
distributor and the addition of a dose control, a filling head, and a subdose
flow branch
for each filling position to be added.
10 The repeatability error of the master dose may be distributed
among the subdoses
in dose ratio for each subdose, measured dose to dose or in a compiled
average, so that
the repeatability error of each subdose may be identical in percentage terms
to that of the
master dose.
Precise synchronous actuation, operation and closing of all functioning dosing
valves may be electronically controlled, monitored and alarmed, assuring that
asynchronous operation is prevented and thus preventing the hydraulic
acceleration or
increase of flow rate into containers being filled resulting from asynchronous
dosing
valve operation.
Filling heads may be grouped into two or more pluralities, all pluralities
having
the same number of filling heads, so that each container in a plurality of
containers
receives a calibrated subdose fill at a first indexed filling position and
additional
calibrated subdose fills at each subsequent and corresponding indexed filing
position,
until the subdoses sequentially and separately filled into each container sum
to be the
desired total container dose.
The subdose from each dose control may be further hydraulically subdivided
into
two or more fractions, so that each container in an indexed group of
containers receives a
fractional portion of its calibrated subdose at a first grouped indexing
position, and
additional fractions of its calibrated subdose at each subsequent and
corresponding
grouped indexing position, until the complete subdose is filled into each
container.
The plurality of subdose flow branches from the distributor may be split into
two
equal pluralities, each plurality alternately dosing correct subdoses to
container filling
positions located on parallel container indexing lanes, for the purpose of
implementing a
dual lane output liquid filing machine providing higher output speeds.
All configuration and calibration data for operation of the dosing invention,
including, but not limited to, master dose pump flow rate, master dose pump or
master
CA 02869379 2014-10-31
0MsOlUSp
11
dose flow meter dose pulse count, dose control calibrations, adjustment
position or pulse
count for each dose control, and filling head size and type, may all be
grouped and stored
electronically for re-use as operating set up parameters, thus allowing
filling of a
particular liquid at a particular subdose into a particular container to be re-
implemented
without the requirement of repetition of a calibration procedure.
A single master dose sample filling head can be utilized to establish the
desired
master dose volume or weight in accordance with equation (2), using the
calibration
method disclosed in equation (4). In one embodiment, the present disclosure
provides for the
use of only a single dosing pump, a simple flow branch divider and a dose
control fitted into
each flow branch, and synchronously operating dosing valves to provide filling
doses to any
plurality of filling heads in an automatic filling machine. This dosing method
and apparatus may
be useable with containers filled in groups with a desired dose delivered into
each grouped
container with each filling cycle. It may use a positive displacement pump to
generate the
motive force for flow; and may determine and define container filling dose
using known means
and methods for positive displacement pump volumetric and net weight fills.
The reduced complexity of the method and apparatus in the present disclosure,
while
delivering fully comparable performance, confers an improvement in reliability
and, as a
corollary, reduced and simplified maintenance.
This dosing method and apparatus results in numerous advantages over known
practice
and designs. Using the apparatus and method of this disclosure, only one servo-
pump is used,
and therefore, only one dosing pump is used, The single dosing pump provides
liquid to all
dosing positions. Servo-pumps are expensive and relatively complex, and are
often the most
expensive discrete devices in the filling machine,
A significant reduction in the liquid flow pathway components allows simpler
and more
rapid cleaning with a lower volume of effluents. This reduces costs, speeds,
changeover, and
improves machine productivity.
A filler constructed using the disclosed filling and liquid flow pathway can
be
substantially smaller in dimensions over known designs. This size reduction
frees up highly
valuable manufacturing floor space.
Expansion of the number of filling heads to meet higher production needs on a
machine
embodying the new filling method and apparatus requires only a change in the
branch flow
divider, addition of dose controls, and addition and connection of filling
heads.
CA 02869379 2014-10-31
=
OMS01.114
12
The overall machine control structure and its cost, typically implemented
using a
programmable logic controller (PLC), are inherently simpler and lower
respectively with the use
of the method and apparatus set forth in the present disclosure.
In the case where net weight filling is implemented in the new invention using
only a
single Coriolis mass flow meter, compared with a flow meter for every head in
older designs,
the cost reduction and simplification is of similar magnitude to the cost
reduction and
simplification gained by the use of only a single servo-pump.
The new liquid filling method and apparatus are comparable in the range of use
and
application to known multi-pump designs, from the perspective of filling
speed, range and types
of liquids to be filled, filling or dose volume or mass, temperature range of
operation, dose
repeatability and set-point accuracy, and ability to operate in hazardous
locations.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic view of a first embodiment of the liquid dosing
invention,
FIG, 2 is a schematic view of a second embodiment of the liquid dosing
invention.
PIG. 3 is a schematic view of the first embodiment of the liquid dosing
invention
providing a master dose sample filling head.
FIG. 4 is a schematic view of the second embodiment of the liquid dosing
invention providing a master dose sample filling head.
FIG. 5 is a schematic view of the first embodiment of a step filling
arrangement
of the liquid dosing invention.
FIG. 6 is a schematic view of the second embodiment of a step filling
arrangement of the liquid dosing invention.
FIG. 7 is a schematic view of the first embodiment of a dual lane filling
arrangement of the liquid dosing invention.
FIG. 8 is a side view of an example filling head.
DETAILED DESCRIPTION
The present disclosure describes a liquid dosing or filling method and
apparatus
in which a single master dose pump is supplied with the liquid to be filled by
a single
outlet reservoir or by a single flow source liquid supply. In the liquid
filling method and
apparatus, a single master dose pump may operate as the single motive force to
provide a
master dose which is hydraulically subdivided into a plurality of equal
subdoses. The
CA 02869379 2014-10-31
OMSOlUSp
13
dosing method and apparatus disclosed in this specification comprises several
embodiments.
A first embodiment is disclosed in Figure 1, and generallyindicated by
reference
numeral 10. A liquid supply source, generally a supply reservoir 20, may be
suitably
sized to accommodate outflow demand and may be located proximate to the master
dose
pump 24. The supply reservoir 20 may be supplied with a suitable level control
device
(not illustrated) to allow for resupply from a bulk source. The supply can
alternatively
be a flow conduit from a remote bulk supply of the liquid to be dispensed.
The supply reservoir 20 is hydraulically connected to the master dose pump 24.
The master dose pump 24 may be a positive displacement pump, and may be of any
suitable positive displacement type. Some examples include linear piston
pumps, and
rotary lobe, gear and circumferential piston types. Progressive cavity, sine
rotor,
peristaltic, vane and diaphragm pumps may also be used,
The master dose pump 24 may be driven by an electric servo motor 28. Servo
motor 28 may be rotary or linear in output and may directly drive the pump or
may
operate through suitable gear reduction. Alternatively, other conventional
means of
operating the master dose pump may be employed such as pneumatic or hydraulic
drive
arrangements. Controller 30 controls the operation of the pump.
In operation, the master dose pump 24 operates intermittently to produce a
master
dose based upon the displacement of the pump, at a suitable flow rate based
upon the
rate of motion of the pump. With piston pumps, the rate of linear motion
defines flow
rate, and with rotary positive displacement pumps, the rate of rotation
defines the flow
rate. A dose is produced by initiating the pump motion at the desired flow
rate and
subsequently ending the pump motion. This method for controlling dose flow
rate and
dose quantity is well known in the liquid filling art and is extensively
practiced
commercially, as with the PRO/PILL and SERVO/FILL products manufactured by
Oden Machinery Inc. of Tonawanda NY.
Flow rate and displaced dose quantity are both derived electronically. In the
case
of linear displacement pumps, pump motion and rate may be measured using a
measuring device 32 such as a linear encoder, linear variable differential
transformer
(LVDT), or similar, and the signals may be analog or digital. With rotary
displacement
pumps, the measuring device 32 may be an analog or digital rotary encoder,
resolver or
other measuring devices known in the art.
As understood by one knowledgeable in the liquid filling field, establishing
and
controlling the rate of flow of a particular liquid into a particular
container is essential
for correct filling and is widely variable in application, depending on such
variables as
container form, dose size, and liquid properties such as viscosity and
foaminess. In the
CA 02869379 2014-10-31
OMSOlUSp
14
prior art, each filling head is supplied by a discrete positive displacement
pump.
Referring again to Figure I, the entire liquid flow pathway is hydraulic in
operation. The flow rate from any one of the plurality of filling heads 36A,
36B, 36C
and 36D may be adjustably derived from the single master dose pump 24. The
master
dose pump 24 serves as the single motive force for liquid flow in the dosing
apparatus.
The master dose pump 24 must be sized and adjusted to produce a flow rate
which is a
multiple of the desired flow rate at each individual filling head.
This can be understood by example. Consider a four filling position version of
the dosing apparatus as shown in FIG. 1, where each filling head defines a
filling
position, In this example, it is desired to have a range of possible flow
rates from each
filling head from near zero, up to 25 liters per minute maximum. To
accommodate the
maximum flow at all dosing positions the master dose pump must provide a
maximum
flow rate of 100 liters per minute. This flow relationship, unique to this
dosing
apparatus, can be defined by the expression:
MDPFMAX = MFV x NFH (10)
where MDPFMAX is the master dose pump flow maximum required, MFV is the
maximum flow required of any individual filling head, and NFH is the number of
filling
heads in the apparatus. The flow and dose from the master dose pump is equally
divided
among the plurality of dosing positions.
Liquid flow displaced by the master dose pump 24 is communicated via a
suitable flow conduit to a dose distributor 40. Dose distributor 40
hydraulically
subdivides the dose produced by the master dose pump 24 into a plurality of
subdoses
which are approximately equal to one another. As shown in FIG. I, the liquid
dose
distributor 40 has four subdose branch flow outlets 42A, 42B, 42C, and 42D.
However,
the number of subdose branch flow outlets 42 may be more or less than four,
and will be
the same as the number of filling heads 36.
The dose distributor 40 may take many forms including, but not limited to, a
horizontal or vertical cylindrical liquid manifold or a fabricated tubing
branched array.
As shown in FIG. 1, the distributor is a generally round conical structure,
with liquid
entry 46 at the bottom, and the subdose branch flow outlets 42 at the top,
although other
shapes and geometries could be used. The generally round conical structure
provides a
highly stable and repeatable hydraulic subdivision of the master dose with
minimal flow
turbulence and minimal flow induced pressure boundaries or anomalies within
the
distributor lumen. The aspect ratio of the distributor diameter to height may
be at least
1:1 and preferably greater,
Each subdose flows out of the dose distributor 40 via a subdose branch flow
outlet 42 and into a subdose flow branch 50. Each subdose branch flow outlet
42 may be
CA 02869379 2014-10-31
=
OMSOIUSp
manufactured to a tight tolerance to assure a relatively even division of the
master dose
among the plurality of flow branches 50. As shown, there are four subdose flow
branches
50A, 50B, 50C, and 50D, but the actual number may be more or less, depending
on the
number of filling heads.
3 Each subdose flow branch 50 may comprise a flow conduit, typically
a rigid tube
or a flexible hose having a semi-rigid structure, suited to the flows,
pressures, motions,
and chemistries to which it will be subjected. The subdose flow branch 50 may
be
selected for its consistent repeatability of internal flow diameter, and may
be found to be
most suited when within two (2) percent of the supplier stated diameter, and
more
10 optimally, within one (1) percent. Each subdose flow branch 50 may be
fabricated such
that all subdose flow branches 50A, 50B, 50C, and 50D are within a net flow
length of
one (1) percent from one subdose flow branch to the next. Because of this and
the
dimensional precision of the subdose branch flow outlets 42, each subdose as
measured
at the discharge end of its subdose flow branch 50 is within four (4) percent
of the mean
15 subdose, where the mean subdose is defined by the sum of all subdoses,
divided by the
number of subdoses.
Again referring to the embodiment illustrated in FIG. 1, each subdose flow
branch 50 terminates at the inflow fitting or port 54 of an adjustable dose
control, 56A,
56B, 56C and 56D. Each of the adjustable dose controls defines a subdose to be
delivered to a container. Each of the adjustable dose controls 56 found in the
liquid flow
pathway of each subdose flow branch 50 may be adjusted in conjunction with all
others
in the apparatus to achieve subdoses which are all approximately equal to one
another.
The subdoses may all be within a stated accuracy range relative to the mean
subdose,
where the mean subdose is defined as the sum of all subdoses in the apparatus
divided by
the number of subdoses.
The adjustable dose control 56 may be constructed of rigid materials suitable
to
the pressures, flows and chemistries of the anticipated service. Each
adjustable dose
control 56 may have flow pathway dimensions that are tightly controlled in
fabrication,
thereby enabling each adjustable dose control to be interchangeable with every
other
within the given dosing apparatus. Each adjustable dose control 56 may have an
inflow
port 54, and an outfeed port 60. Each adjustable dose control 56 may also have
a dose
adjustment mechanism 62. Each dose adjustment mechanism 62 may operate
manually
or automatically. Each dose adjustment mechanism 62 may be capable of altering
the
dose flowing through the device by an increment of at least ten (10) percent,
measured
by volume or weight. The adjustment of dose may be essentially linear within
the
adjustment range of the device.
A conduit 64 may extend between the outfeed port 60 of each adjustable dose
CA 02869379 2014-10-31
OMSOlUSp
16
control 56 and the corresponding filling heads 36, and each branch may have an
adjustable dose control and a filling head associated with it, and each
filling head defines
a filling position. These filling heads 36, also termed filling nozzles,
dosing nozzles,
filling valves, dosing valves, and dosing heads, may be of many known designs,
depending on the nature and characteristics of the liquid being dosed, the
dose size, and
flow rates. A filling head is shown in FIG. 8, and is similar to the filling
head shown in
US Patent 6,669,051. However, other configurations of filling heads may be
used. Each
filling head 36 is actively valved to provide control of the flow capability
and to allow
each of the filling heads 36 to be opened or closed simultaneously. Controller
30 controls
the operation of the filling heads. Each of the plurality of filling heads 36
may be
dimensionally controlled so that interchanging the filling heads 36 with one
another
results in test doses that vary by no more than one (1) percent by weight or
volume with
respect to one another.
The operation of the filling heads may be repeatable from one operation to the
next to within two (2) milliseconds of the desired duration, Al! filling heads
36 operate
synchronously, even though the actuation of each individual filling head is
discrete.
The synchronized opening and closing of each filling head 36 enables a single
master dose to be divided into a plurality of equal subdoses using only a
single dose-
defining motive force. This method of operation also assures that there is no
hydraulic
acceleration of flow rate as would occur in any flow branch in which flow
continued
after the closure of one or more of the other dose'valves in the apparatus.
Such hydraulic
acceleration would both alter the size of the subdose and create excess
turbulence in
containers being filled. The excess turbulence could result in the blow out of
liquid from
containers. Liquid dosing systems are generally adjusted to maximize the
tolerable flow
rate into containers in order to minimize fill time while maximizing machine
output
speed and productivity. Thus, there is little or no tolerance for asynchronous
dosing
valve operation,
The actuation time to open or close a filling head 36 is electronically
measured
for each filling head, with each actuation, thereby enabling the early
detection and
notification of any malfunction of any filling head 36. This, in turn, allows
the
prevention of incorrect or inaccurate fills Or hydraulic accelerations of
flow.
The dosing apparatus of this disclosure incorporates hydraulic subdivision of
the
master dose into equal subdoses. Therefore, it is preferable that all filling
heads not only
open and close at the same time and at the same rate, but also that any
failure resulting in
premature closing or shut-off of a filling head during a dosing event be
detected, Such
failure of a filling head may result in incorrect subdoses being delivered by
the remaining
functioning filling heads, Each filling head may be provided with an open-to-
flow
CA 02869379 2014-10-31
0MsOlUSp
17
sensor (not illustrated). The open-to-flow sensor may be continuously
monitored during
a dosing event. The loss of full open status on any filling head may result in
termination
of the dose cycle and activation of an alarm (not shown). The alarm may
specify the
failed filling head,
In operation, the functioning filling apparatus is hydraulic, from the liquid
supply
20 to the adjustable dose controls 56. As a result, the plurality of filling
heads 36 operate
synchronously with the master dose pump 24. This may be accomplished
electronically
by linking the opening and closing of the filling heads 36 to the master dose
pump
displacement motion, Thus, all filling heads 36 must be known to be open
before pump
displacement motion is allowed, and synchronized closing of all filling heads
is not
allowed until pump displacement motion is ended or nearly ended. One method
for
interlocking the pump displacement motion and the operation of the filling
heads 36 is to
interlock the signal that enables the operation of the pump drive to the
filling head
opening, and using a missing pulse detector circuit for detection of end of
pump motion
at the completion of a master dose. Those skilled in the art will recognize
that many
other methods may be used to accomplish the same result, and all fall within
the scope of
this invention,
It will be apparent to one skilled in the liquid dosing arts that many
variations of
the first embodiment of the invention are possible, all within the scope of
the invention.
In particular, the adjustable dose controls 56 can be directly connected to
the subdose
branch flow outlets 42 of the dose distributor 40. Likewise, the adjustable
dose controls
56 can be directly connected to the filling heads 36, or incorporated in the
dosing head
structure.
FIG, 1 illustrates a plurality of containers 66A, 66B, 66C, 660 to be filled
with
liquid. As shown, the number of containers 66 is equal to the number of
filling heads 36
in the dosing apparatus. The containers 66 generally may be resting on a
moveable
conveyor surface. The containers 66 are spaced and located under filling heads
36 by a
conventional container indexing system 68.
The master dose pump 24 may be a positive displacement pump and as such, may
define a master dose which is volumetric.
In a second embodiment, shown in FIG. 2, a liquid flow meter 70 is positioned
in
the liquid flow pathway between the outfeed of the master dose pump 24, and
the liquid
entry 46 of the dose distributor 40. The flow meter 70 may be a volumetric
flow meter,
such as a magnetic flow meter or another type of volumetric flow meter.
Alternatively,
the flow meter 70 may be a mass flow meter, such as a Coriolis mass flow meter
or
another type of mass flow meter.
When using a volumetric flow meter 70, master dose pump 24 provides the
CA 02869379 2014-10-31
0Ms011.1Sp
18
single motive force for liquid flow through the dosing apparatus, but does not
define the
volumetric master dose. Instead, the volumetric master dose is defined by the
flow meter
70, generally as a pulse train output. In some cases, the master dose pump
encoder
pulses are counted and compared with the flow meter pulse count on a dose
cycle by
dose cycle basis as a means of providing checking, verification and validation
of
performance of the volumetric flow meter, Suitable data bases, averages, and
alarm
functions are provided.
When liquid flow meter 70 is a mass flow meter, the master dose is a mass or
net
weight dose, termed the master mass dose. In this embodiment, pump 24 provides
the
single motive force for liquid flow through the dosing apparatus, but does not
define the
master dose, Instead, the master mass dose is defined by the mass flow meter,
generally
as a pulse train output which is used as previously described for the master
dose pump
encoder. Dose comparison and alarming with the master dose pump as described
for the
volumetric flow meter case may also be used.
As previously discussed, each liquid flow component in each subdose flow
branch is fabricated with a high degree of dimensional precision, allowing a
relatively
even division of the master dose to the plurality of subdose filling
positions, even prior
to dose control adjustment. This flow division relationship, from one flow
branch to the
next, may be preserved by a permanent marking affixed to each flow component,
assuring that each component is replaced in the same flow branch position
after removal
for any reason.
The methods of configuring and calibrating the apparatus to establish a master
dose and a plurality of equal subdoses will now be discussed in detail.
Because the apparatus disclosed in FIG, 1 and FIG. 2 is hydraulic in
operation,
the volumetric or master mass dose must be equal to the sum of all subdoses.
Thus, for
example, in a system with four subdose filling positions:
MD = SD, + S. + S. + SD, (11)
where MD is the mass or volume of the master dose and SD, - SD, are the masses
or
volumes of the four subdoses. This expression can be generalized as:
MD = Sp, -I- Sp, -I- + S, (12)
where X is the number of subdoses and Sim is the mass or volume of the X
subdose.
When all subdoses produced from a single master dose cycle are collected and
measured,
the volume or mass of the master dose can be determined,
After the master dose has been adjusted and calibrated, and the dose control
in
each flow branch has been utilized to equalize each subdose, the mathematical
relationship between the mass or volume of the master dose (MD) and the mass
or
volume of the plurality of subdoses (SD) can be expressed as:
CA 02869379 2014-10-31
11rs 19
M = SpxX (13)
or
S,õ M,õ + X (14)
where 5,, isthe desired target subdose, and X is the number of subdoses in the
operating
pa1iiljtyoSfPclosing positions. Thus, to arrive at subdoses of the desired
amount, the
master dose should first be calibrated to be equal to a multiple of the
desired subdose
setpoint. The master dose calibration to meet this requirement can be
accomplished using
three different methods.
With the first method, a test cycle of the dosing apparatus is made and all
subdoses are collected and measured. The total of either the volumes or the
masses of all
subdoses constitutes the trial master dose quantity. The total pulses
generated by the
master dose defining apparatus are noted, as previously explained. The master
dose
apparatus is then adjusted for its dose pulse preset using the following
formula:
TARMD x TRIMDPC = TARMDPC (15)
TR1MD
where TARMD is the target master dose, TR1MD is the trial master dose, TRIMDPC
is
the trial master dose pulse count, and TARMDPC is the target master dose pulse
count.
The calculated target master dose pulse count may be entered either manually
or
automatically into the electronic control system governing the operation of
the master
dose apparatus, and a second trial master dose may be collected and measured.
If
required, the master dose calibration sequence may be repeated until a master
dose of the
required amount is achieved.
This calibration process is repeated until the master dose is within the
desired
tolerance, preferably one (1) percent of the established target. This level of
dose set
point accuracy is typically achieved within three repetitions of the master
dose
calibration sequence.
With the second method of master dose calibration an approximate calibration
of
master dose is made, followed by equalization of each subdose. A final master
dose
calibration occurs after completion of the subdose equalization calibration
sequence.
This second method relies on the fact that each component of flow structure in
the
product distributor and in each flow branch are of sufficient dimensional
precision that
each unadjusted subdose is within five (5) percent of every other subdose.
Therefore,
users may make a first master dose test cycle and sample only one subdose. The
subdose
sampled may be used as the basis for one additional master dose adjustment
(using the
formula above) to arrive at a master dose that is within 5% of the desired
dose size.
The second master dose adjustment method requires only two master dose
CA 02869379 2014-10-31
OMSOlUSp
calibration cycles and only two subdose samples. This contrasts with the first
method
wherein each subdose position may be sampled up to three times. Thus, for
example,
with ten filling positions the first method requires collecting and measuring
thirty (30)
subdoses, while the second method requires collecting and measuring only two
(2)
5 subdoses. Furthermore, and in contrast to the first method described,
the second method
does not require additional subdoses to be sampled with increases in the
number of
filling heads to be used.
The third method of master dose calibration may be discussed by reference to
FIGS. 3 and 4. The embodiment shown in FIG. 3 illustrates a master dose
calibration
10 filling valve 74 operable with the master dose pump 24. The embodiment
illustrated in
FIG. 4 shows a master dose calibration filling valve 74 operable with the
master dose
pump 24, and with liquid flow meter 70 positioned downstream from the
discharge of
master dose pump 24. This method allows direct sampling and adjustment of the
master
dose, with a single sample dose collection point. As with the first method,
three (3)
15 sampling and adjustment cycles are generally adequate to achieve a
master dose set point
within one (1) percent as measured by mass or volume of the desired master
dose. In
this method of dose calibration, filling heads 36 are initially disabled, and
master dose
calibration filling valve 74 is enabled, thereby enabling the collection of
the entire
calibration master dose in one location. When master dose pump 24 is used to
define the
20 master dose, there may be some change in the amount of liquid displaced
per unit of
motion of the pump as a function of a change in back pressure acting on the
pump
discharge. This change in back pressure may result from the different pump
discharge
flow structure acting on the pump when the master dose flows to the container
filling
heads, compared to when the master dose flows to the sample valves. Therefore,
the
third master dose calibration method may require a final calibration
(generally the third
master dose calibration cycle) after the dose controls have been adjusted.
This final
master dose calibration is completed by delivering the master dose to all
synchronously
operating subdose filling heads, and sampling one or more of the subdose
filling heads.
As with all calibration and operating parameters for this dosing method and
apparatus, the master dose calibration data may be stored in the electronic
control
apparatus of the invention. This data may be used to reconfigure the apparatus
as desired
from time to time.
The methods for adjustment and calibration of the plurality of subdose flow
branches in order to equalize the target subdoses to be filled into containers
will now be
described.
The liquid dosing apparatus uses a hydraulic dose division apparatus to divide
the
master dose into equal subdoses, wherein each subdose constitutes a target
container
CA 02869379 2014-10-31
OMSOlUSp
21
filling dose.
Division of a master dose into equal target subdoses may be accomplished by
adjustment of the dose controls found in each of the plurality of subdose flow
branches.
Referring again to FIG. I, adjustable dose control 56 may be either manually
or
automatically adjustable using dose adjustment mechanism 62.
The master dose is equal to the total of all subdoses for a given dosing
episode,
where a dosing episode is one sequence of filling a container at each filling
head. The
master dose may be divided into equal subdoses by dividing the mass or volume
of the
master dose by the number of containers to be filled in each dosing episode.
For
example, referring to FIG. 1, if the master dose is 1000 ml,, each of the four
containers
shown will be filled with 250 ml. of liquid.
The adjustable dose control 56 in each subdose flow branch 50 may be adjusted
as appropriate to increase or decrease the dose delivered to its filling head
36. The dose
adjustment mechanism 62 is initially in a neutral or center position and may
generally be
varied to increase or decrease the dose amount by around ten (10) percent of
the
unadjusted dose. This range of adjustment is adequate to allow the adjustment
of any
given subdose to be equal to all other subdoses, since each unadjusted subdose
is
typically within five (5) percent of the average of all other unadjusted
subdoses as
discussed above.
Because the apparatus is hydraulic, any subdose portion which is altered in a
given branch alters subdoses in all of the other branches as well. Thus, for
example, if a
subdose is increased in one branch, the subdoses in all other unadjusted
branches will
decrease. Conversely, if a smaller portion of the master dose is allowed in a
branch by
adjustment of the branch dose control, the subdoses in all other unadjusted
branches will
increase.
The increase or decrease in subdose from adjustment of a flow branch is
ratiometrically distributed to each unadjusted flow branch in proportion to
the ratio of
the actual subdose on a given unadjusted flow branch to the sum of all
subdoses from all
unadjusted flow branches.
Two methods of subdose equalization adjustment will be discussed. In the first
method, a trial subdose is collected and measured by weight or volume from
each
operating filling head in the apparatus. The difference in weight or volume of
each of
the trial subdoses from the target subdose, where the target subdose is common
to all
dosing positions, is determined. The increment of error is determined using
the formula:
TARSD ¨ TRISD = SDE (16)
where TARSD is the desired target subdose, TRISD is a trial subdose, and SDE
is the
CA 02869379 2014-10-31
0M801USp
22
subdose error. All terms are in units of volume or in units of weight.
If the trial subdose is below the target subdose, the dose control must be
adjusted
to increase the subdose. Conversely, if the trial subdose is larger than the
target subdose,
the dose control must be adjusted to decrease the subdose,
Each adjustable dose control 56 in each subdose flow branch 50 of the
apparatus
is substantially identical to every other. Each adjustable dose control 56 has
a
substantially identical dose adjustment mechanism 62, Each of the plurality of
the dose
adjustment mechanisms 62 may be digitized to allow manipulation based upon
dose
adjustment computations. In cases where the adjustable dose controls 56 are
manually
adjustable, the adjustable dose controls may have an incremented scale with a
centerpoint reading zero, and graduations for negative adjustment for subdose
reduction,
and graduations for positive adjustment for subdose increase. The resolution
of the
scaled divisions may vary, but most typically are intended to adjust to one
tenth (1/10) of
a percent or less of the subdose setpoint. Adjustable dose controls which are
automated
may generally be controlled by the apparatus programmable logic controller
(PLC), and
may operate in the same manner as the manual version and with similar
resolution.
Once the subdose error for each subdose has been computed, all dose controls
may be adjusted as required. The increment a adjustment for each dose control
requires
calibration of the dose control itself, so that each scale or position sensor
increment
represents a known increment of actual dose change in weight or volume, The
scaling of
each dose control in a given operating apparatus may be treated as the same
from one
dose control to the next, Therefore, only one dose control need be initially
calibrated,
and the resulting weight or volume change per increment of adjustment may be
utilized
in all dose control positions.
Dose control calibration may be initially accomplished by moving the dose
adjustment mechanism 62 on one adjustable dose control 56 by an arbitrary
number of
scale increments or divisions, and then cycling the dosing apparatus to
produce a second
set of subdoses on all dosing positions. On the one given sample dose
position, the new
subdose amount is measured and the result applied to the following dose
control
calibration formula:
(FTD ¨ STD) = CUPI (17)
SI
where FM is the first trial dose in weight or volume, STD is the second trial
dose in
weight or volume. Si is the number of adjusted dose control scale increments,
and CUPI
is the resulting calibrated units per increment value expressed in weight or
volume per
scale increment.
CA 02869379 2014-10-31
ONIsOlUSp
23
For clarity, consider the following dose control calibration example:
First trial dose (FTD) = 260 grams
Scale increments moved (Si) = 25
Second trial dose (STD) .255 grams
Calibrated units per increment (CUPP = 0,2 grams
Each dose control is essentially linear in either direction of correction and
as a result may
be calibrated by increasing or decreasing dose. In the above example, the dose
was
decreased. Once determined, the dose control calibration for a given amount of
liquid to
be filled into a given container can be stored electronically along with the
other
configuration parameters set forth in this specification.
The dose control calibration method described is an initial or first
calibration, and
may be used for a first adjustment of each adjustable dose control 56. The
accuracy of
the initial dose control calibration may be improved as part of the subdose
adjustment
procedure.
Having established the error of each subdose based upon a first trial dose
cycle of
the apparatus, and having completed an initial calibration of the dose
controls for each
operating dose position using the dose control trial dose method set forth,
each subdose
may be adjusted to be equal to every other subdose where each subdose is of
the desired
fill weight or volume.
The first method for subdose adjustment consists of determining the correct
dose
control adjustment to be made at each filling head position, adjusting all
positions,
cycling the apparatus to produce an adjusted subdose at each position and
measuring the
resultant weight or volume for each.
Dose control adjustment is made by dividing each subdose error, whether
positive or negative, by the calibrated units per adjustment increment, which
yields the
number of scale increments to be adjusted for that subdose. This computation
is given
by the formula:
SDE/CUPI = SIC (18)
where SDE is the positive or negative subdose error, CUPI is the calibrated
units per
increment of adjustment of the dose control, and SIC is the number of scale
increments
for correction of the trial subdose. A positive SIC result requires an
increase in the
subdose, and a negative SIC result requires a decrease in the sub:lose.
An example of this subdose adjustment procedure will help to clarify and
illustrate this first method:
Consider a four filling head embodiment of the dosing invention as shown in
FIG.1, where the dose controls have been calibrated to a change in dose of
0,10 grams
CA 02869379 2014-10-31
OMSOlUSp
24
(g.) per increment of adjustment, and each desired subdose is 1000g., giving a
master
dose of 4000g.
CA 02869379 2014-10-31
0MsOlUSp
The computation sequence would be as follows:
OPERATION HEAD 1 MAD 2 HEAD 3 Liga
I. First Trial Dose 970g. 1030g. 1020g. 980g.
5 2. Master Dose Check 970g. + 1030g. + 1020g. +
980g. = 4000g.
3. Subdose Error +30g. -30g. -20g.
+20g.
4. Dose control +300 -300 -200 +200
Adjustment Increments
10 5. Theoretical New 1000g. 1000g. 1000g. 1000g,
Subdose
6. Master Dose Check 1000g. + 1000g. + 1000g. + 1000g. =
4000g.
Following this computation and adjustment sequence, the master dose pump 24 is
again cycled, and subdoses are collected and measured at each filling head 36.
Each
subdose will be closer to the target dose value, but may not be at the target
value,
Accordingly, the computational sequence may be repeated, dose controls
adjusted, and
another set of subdoses collected and measured. With each successive
adjustment and
sample cycle, the number of increments adjusted decreases, and the dose error
of each
subdose decreases. Typically, after one to three adjustment cycles, each
subdose is
within an acceptable tolerance, generally one (1) percent of the target
subdose. Thus, for
example, on an apparatus with ten filling heads, subdose setpoints may be
achieved with
no more than 30 subdose samples, three at each position.
As with the other apparatus setup parameters, the dose control calibration
settings
for a given liquid and subdose may be electronically saved for recall and
reuse. Thus,
the described master dose and subdose calibration sequences may need to be
done only
one time.
With each subdose sample cycle, the accuracy of the dose control calibration
used to adjust each subdose may be improved by measuring the increment of dose
change for each subdose after an adjustment of the dose controls, averaging
the
increment of dose change across all subdose positions, and then
correspondingly
averaging increments or, divisions or pulses of adjustment for all dose
controls, and then
applying these data to the following dose control calibration formula:
ADC/ASI = RCUFI (19)
CA 02869379 2014-10-31
0MsOlUSp
26
where ADC is the average dose change across the operating dosing positions,
ASI is the
average scale increments of dose control adjustment across the operating dose
positions
and RCUPI is the resultant recalibrated units per increment of dose control
adjustment.
With each subdose sample and adjustment cycle, the rate of adjustment
improves,
and therefore, the number of sample cycles to reach subdoses which are equal
to one
another arid within the desired tolerance of subdose setpoint may be reduced.
As with the other apparatus setup parameters, the dose control calibration
settings
for a given liquid and a given subdose may be electronically saved for recall
and reuse.
After subdose setpoint adjustment has been completed, the repeatability of
each
subdose from one dosing event to the next is a direct function of the
repeatability of the
master dose. Therefore, a given subdose repeatability error is related to the
master dose
repeatability error, and the percentage repeatability error of each subdose is
the same as
the percentage repeatability error of the master dose.
In a second method of subdose adjustment and calibration, the master dose pump
is cycled, producing synchronous subdoses at all functioning filling heads.
The subdose
at a first position is collected and measured and the dose control on that
head is adjusted
according to the previously disclosed procedure. Then another dose cycle is
initiated and
the subdose at a next head is measured and adjusted. This sequence continues,
one dose
position at a time, until all filling heads have been adjusted. The process
may then be
repeated, and typically one to three samples per position are taken, until
each subdose is
within an acceptable tolerance of the target setpoint. The total number of
subdoses to
achieve calibration increases as the number of dosing positions in the
apparatus
increases, causing the use of a much greater amount of the liquid to be
filled.
Referring now to FIG. 5, in another embodiment, the subdose produced by the
adjustable dose control 56 on any given subdose flow branch 50 may be
hydraulically
subdivided into two parts to allow container step filling. The average of the
divided
subdose totals is equal' to the desired subdose, which is equal to the desired
target fill for
each container, although the sizes of each of the two parts of the total
subdose may differ
from one another. Containers may be sequentially filled, first at a first
filling head with a
first portion of a subdose, then at a second filling head with a second
portion of the
subdose, thereby completely filling the container with the desired dose. For
example,
one container 10 may be partially filled at filling head 36A at the first
index position 84
with a first portion of the subdose, then indexed to a second filling position
86 for the
second portion of the subdose fill. Because the size of the first and second
portions of
each subdose are highly repeatable, the total dose received by each container
using this
CA 02869379 2014-10-31
01As011.14
27
method is as accurate in repeatability as in the case where the entire subdose
is delivered
by a single filling head.
This embodiment may be used where the behavior of the liquid being dosed
limits the flow rate into the container, for example, due to turbulence
effects or foaming.
In these cases, by subdividing the subdose, the absolute fill time per
indexing cycle may
be reduced, and the flow rate into the container may also be increased,
thereby reducing
the fill time, and increasing the output rate of the machine. The subdivision
of the
subdose can be of any ratio desired since each container in the indexing queue
is always
dosed at its corresponding filling heads.
1.0 Alternatively, step filling may be implemented by indexing
containers
sequentially under two equivalent groups of subdose filling heads 36, each
subdose
position having its own adjustable dose control 56 as shown in FIG. 6. This
method has
all of the same capabilities and advantages as the previous method, but has
greater
complexity of calibration and setup and the higher cost of additional dose
controls.
As shown in FIG. 6, a "Y" fitting 58 is disposed downstream of each adjustable
dose control 56. However, the fitting could be of another configuration that
divides the
flow from the adjustable dose control 56 into two separate streams, such as a
tee fitting.
Conduits extend from each downstream end of the fitting 58 to a filling head
36. The
fitting 58 divides the liquid stream into two substantially equal flows. This
allows two
containers to be filled simultaneously with equal portions of liquid.
Referring now to FIG. 7, a dual lane filling machine has two lanes 80A, 8013
of
containers being filled by the liquid dosing apparatus. Dual lane fillers
allow increased
machine output speeds (measured in containers per minute) compared with single
lane
configurations.
In the embodiment shown in FIG. 7, the master dose produced by master dose
pump 24 or by liquid flow meter 70 (as shown in FIG. 2) can be directed to one
of two or
more side branches 76 by means of the flow fitting 78, where the flow fitting
78 divides
the liquid flow, directing it into one of a plurality of the side branches 76.
Flow fitting 78
may be a tee fitting or any other appropriate configuration that allows the
flow to be
directed to side branches 76. Each side branch 76 out of the flow fitting 78
leads to a
complete dosing apparatus. Each complete dosing apparatus consists of a dose
distributor 40, adjustable dose controls 56, and filling heads 36,
The two complete dosing apparatuses may operate alternately. When the first
apparatus 10A is delivering subdoses into a first set of containers 66A on the
first lane
80A of conveyor 82, a second set of containers 66B are being indexed into
filling
positions on the second lane 80B of conveyor 82. With the completion of
filling on first
lane 80A, filling can begin on second lane 80B. In this arrangement, there is
little or no
CA 02869379 2014-10-31
OMsOlUSp
28
delay in the start of filling due to container indexing at the appropriate
location. This
alternating sequencing confers much higher output speeds than could be
realized on
single lane configurations. With this embodiment, the calibration, setup and
operating
details set forth previously all apply.
The reductions in apparatus allowed when implementing a multi-position liquid
dosing apparatus confers significant technical and commercial advantages. For
example,
the size of a filling machine is generally related to the scope of apparatus
disposed on the
filling machine. The liquid dosing apparatus 1 allows the filling machine to
which it is
fitted to be smaller than would otherwise be possible, while still
demonstrating
comparable performance. This size reduction is significant because functioning
manufacturing square footage may be very expensive.
The burden of cleaning the liquid flow pathway of a liquid filling machine is
a
direct function of the scope and complexity of that pathway, Generally, the
biggest
reason for downtime or unproductive periods in production liquid fillers is
cleaning time
mandated by hygiene and by changeover from one product to another.
Accordingly, the
reduction in cleaning time, and the corresponding reduction in the amount of
cleaning
and rinsing liquid volumes may be economically and environmentally
significant.
The consumption of electric power by an operating liquid filling machine is a
significant portion of its cost of operation. The liquid dosing apparatus
described herein
may consume about one half of the electrical energy required of a comparable
machine
of known prior art design.
The initial capital cost of a production liquid filling machine may be
significant,
and the apparatus described herein, with significantly fewer components than
in prior art
designs, may allow a significant cost reduction when compared to a comparable
machine
of the prior art.
The need to expand or increase the speed and capacity of a filling machine in
production service is common. Currently, capacity expansion is frequently not
possible.
Where it is possible, the size and configuration of the machine structure must
anticipate
expansion, and the expansion cost may be relatively high. To add a single
filling
position with conventional designs requires the use of a completely redundant
dosing
apparatus, including a pump and its associated drive mechanism, which may be
the most
expensive components in a filling position. To add an additional filling
position to the
liquid dosing apparatus disclosed herein requires only a changeout or
alteration of the
dose distributor and the addition of a dose control and filling head, which
are of lower
cost. Further, the compact footprint of the existing machine need not be
initially larger
or increased to allow addition of filling positions.
While a preferred form of this invention has been described above and shown in
CA 02869379 2014-10-31
0M801USp
29
the accompanying drawings, it should be understood that applicant does not
intend to be
limited to the particular details described above and illustrated in the
accompanying
drawings, but intends to be limited only to the scope of the invention as
defined by the
following claims. In this regard, the terms as used in the claims are intended
to include
not only the designs illustrated in the drawings of this application and the
equivalent
designs discussed in the text, but are also intended to cover other
equivalents now known
to those skilled in the art, or those equivalents which may become known to
those skilled
in the art in the future.
